How to spot it

Brown spots with rings like a target, often with a yellow halo, starting on the lowest, oldest leaves. Tomatoes can get dark, sunken spots near the stem.

What it does

Lower leaves yellow and drop, and it works up the plant. With fewer leaves, fruit gets sunburned and the harvest drops.

What to do now

• Pick off spotted lower leaves and throw them away.
• Mulch so rain can't splash soil onto the leaves.
• Spray a copper or Bacillus subtilis product to slow it, following the label.

Keep it away next time

• Grow tomatoes and potatoes in a new spot each year, on a 3-year cycle.
• Stake or cage plants and remove the leaves touching the soil.
• Water at the base, in the morning.
• Grow resistant varieties (such as Mountain Merit, Iron Lady, or Defiant).
• Clear away plant debris in fall.

Helpful supplies

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Plants it affects

See also